Tesla fire caused by road debris not battery flaw: CEO

The CEO of electric car company Tesla Motors Inc on Friday said that a battery in a Model S that caught fire this week was apparently impaled by a metal object.

Elon Musk gave more detail in a blog post about the fire that became an Internet sensation and unsettled Tesla investors. He also defended the car’s battery.

Musk wrote in a blog post that fires are more common in conventional gas-powered vehicles.

“For consumers concerned about fire risk, there should be absolutely zero doubt that it is safer to power a car with a battery than a large tank of highly flammable liquid,” he wrote.

The CEO said that a curved metal object on the road was apparently to blame for the fire on Tuesday. He said the large object’s shape led to a powerful hit on the underside of the vehicle, punching a 7.6cm hole through an armor plate that protects the battery under the passenger compartment.

The car properly contained the blaze in one section of the battery, the company said. The driver was able to exit the highway in the Seattle, Washington, suburb of Kent and get out of the vehicle before flames engulfed the front of the sedan.

Firefighters struggled to extinguish the Tesla fire, finding that the flames reignited. After dismantling the front end of the vehicle and puncturing holes in the battery pack, responders used a circular saw to cut an access hole in the front section to apply water to the battery, according to documents. Only then was the fire extinguished.

Musk said in his blog post that a “road crew” at the scene of the fire identified the curved metal piece, which fell off a tractor trailer, as the apparent culprit.

Tesla shares fell sharply on Wednesday and Thursday after the video of the car fire was circulated online. The stock finished the week down US$9.92, or 5.2 percent, but is still up nearly 400 percent this year.